Hole Saws

[Cheese]

Spyder make some nice hole saws that you can stack hole saws onto so there is a central guide that fits the existing hole size and then will cut larger with another hole saw.

Starrett also makes what they refer to as an "Oops arbor". It allows you to mount a larger hole saw to an arbor and increase the diameter of the existing hole while using the original hole saw as a guide.

 

[Packard]

Spyder make some nice hole saws that you can stack hole saws onto so there is a central guide that fits the existing hole size and then will cut larger with another hole saw.

That won’t work with some 1950s era lock sets. When retrofitting them, they have different center-points and nothing to drill into for that center-point. Drilling oversized to achieve the current diameter will place the lockset in the wrong position. A jig is really the best way to do this.

I used the template to transfer the drill location onto some 3/4” thick sheet stock. I then drilled the hole. And then clamped the resulting jig to the door and drilled the new hole in the correct location. It works well. Rubbing some butcher’s wax to the jig reduces friction.